This invention relates to an anti-glare and anti-fog element having an anti-glare function using an electrochromic phenomenon, and an anti-fog function by a hydrophilic functional film comprising a photocatalyst substance, and more particularly relates to an anti-glare and anti-fog element and an exterior mirror for automobiles, which utilize predetermined color phase at the time of un-operating of the anti-glare function.
An anti-fog element or anti-fog mirror which causes an anti-fog function to be exhibited by a hydrophilic functional film comprising a photocatalyst substance is mentioned for example as conventionally known technology. For example, in JP-A-09-225303 a semiconductor photocatalyst substance and a photocatalyst composition which comprises oxide particle distributed in this semiconductor photocatalyst substance wherein the band gap of the photocatalyst composition is 0.05 eV larger or more than the band gap of a simple semiconductor photocatalyst substance, are produced. In this invention, a photocatalyst composition excellent in photocatalyst activity, having an improved intensity of a photocatalyst film and a substrate with photocatalyst composition can be achieved and can be adapted to such as an anti-fog element.
Further, JP-A-10-36144 proposes an anti-fog element constituted in such a manner that a transparent photocatalytic reaction substance film such as TiO2, is formed on one surface of a transparent substrate member such as a glass substrate, and transparent inorganic oxide substance such as SiO2 is formed thereon to transparently constitute the whole part. In this invention, an anti-fog element is constituted in such a way that an inorganic oxide film in a porous state is formed on the surface of a substrate member such as a glass substrate so that the surface exhibits hydrophilicity. Fall of hydrophilicity can be thus prevented and an anti-fog element which can hold an expected anti-fog property over a long period of time can be achieved.
On the other hand, as a conventional anti-glare element or anti-fog mirror, those which exhibit the antiglare function by electrochromic substance can be mentioned, for example. For example, in JP-09-120088, at least one kind of cathode electrochromic compound, at least one kind of anode electrochromic compound, and single block type self-erasure system solution phase electrochromic device and a device using the same are disclosed. This invention proposes an anti-glare mirror for automobiles serving as a reflection mirror wherein the light of the intensity permissible for a driver is reflected. As an element or a mirror, which allows a coexistence of the above anti-fog function and the anti-glare function, these inventors produced an electrochromic element arranged in such a manner that electrochromic films comprising electochromic substance and electrolysis is arranged between a transparent electrode films provided on two glass substrates, a hydrophilic film comprising a photocatalyst film and a porous inorganic substance are formed on the front surface of the glass substrate of the front side, and with this arrangement, an electrochromic element as a reflector with reflective film formed on the front surface of the backside substrate viewed from the front side substrate is produced. According to this invention, since the surface is formed in hydrophilic state having a photocatalyst function, a photochromic phenomenon of electrochromic films are prevented as well as having an anti-fog function and anti-glare function. This permits an electrochromic element to be realized without adding an ultraviolet-rays absorbent to the aforementioned electrolysis liquid, or with a little bit of addition of the ultraviolet-rays absorbent.
Here, the aforementioned xe2x80x9can electrochromic phenomenonxe2x80x9d is the general term of the phenomenon in which the color of a substance changes with an application of voltage. Here, a xe2x80x9csubstancexe2x80x9d and a xe2x80x9cfilmxe2x80x9d which exhibit such an electrochromic phenomenon are called an xe2x80x9celectrochromic substancexe2x80x9d and xe2x80x9celectrochromic filmsxe2x80x9d, respectively.
If the element or mirror which has an anti-glare function and an anti-fog function thus described is applied to a mirror for such as automobiles, dazzle of catoptric light and surface fog can be prevented, and driver""s visibility can be kept good. Mirrors for automobiles usually include a driver""s seat side mirror and a passenger seat side mirror. A driver""s seat side mirror and a passenger seat side mirror having almost equal anti-glare function and an anti-fog function were conventionally and mainly in use. However, in such a mirror for automobiles, combination of the mirror having the function of necessary minimum for each side of a driver""s seat and a passenger seat, or a different function is increasingly demanded, considering from economical efficiency in recent years.
For example, combination of the aforementioned mirrors for automobiles is considered to be variably carried out such as a combination of a driver""s seat side mirror having the automatic anti-glare function which made reflectance variable, and a passenger seat side mirror having an anti-glare function with fixed reflectance (for example, anti-glare function colored blue) and an anti-fog function. Since especially the mirror having the aforementioned automatic anti-fog function is not colored in comparatively bright state, that is, the state in which an anti-glare function is not needed, for example in the daytime, either of or both of color phase and color tone which each of a driver""s seat side mirror and a passenger seat side mirror presents differs. Especially, when the anti-fog function is not operating in a driver""s seat side mirror, the difference between this color phase and color tone becomes remarkable. Incidentally, generally the attribute of visual and sensory cognition of colors such as red, yellow, green, blue, and purple is meant as the above xe2x80x9ccolor phase.xe2x80x9d The aforementioned xe2x80x9ca color tonexe2x80x9d generally means grades, such as a shade of color, strength, and contrast, and both of these are combined to be referred hereinafter as only xe2x80x9ccolor phasexe2x80x9d.
Furthermore, difference in color phase between the mirror of the aforementioned driver""s seat side and the mirror of a passenger seat side is emphasized in the daytime at the time of not operating of the mirror of the aforementioned driver""s seat side having anti-glare function and when the degree of brightness is comparatively large. Consequently, a man is likely to have comparatively strong sense of incongruity to the difference in color phase between the mirrors caused by such a combination of mirrors. For this reason, in an automobile having different function of mirrors of driver""s seat side and passenger seat side in a corresponding manner respectively, the mirror of the aforementioned driver""s seat side and the mirror of passenger seat side present the almost same color phase. Thus, it is demanded that the combination of the mirror in which a man does not have a sense of incongruity is carried out.
In view of the above-described problems, the object of this invention is to provide an anti-glare and anti-fog element which can be set so as to have both an anti-glare function and an anti-fog function and present a predetermined color phase at the time of un-operating of the aforementioned anti-glare function, and an exterior mirror for automobiles using this anti-glare and anti-fog element.